Method and apparatus for producing bound batts



' June 30, 1942. UNDSAY ETAL v 2,288,095

METHOD AND APPARATUS FOR PRODUCING BOUND BATTS Filed May 25, 1939 2 Sheets-Sheet 1 ZZO/"I jar; O MdUAgfq- Jun'e130, 1942- H. B. LINDSAY l-AL METHOD AND APPARATUS FOR lRQDUCING BOUND BATTS',

Filed May 25,- 1959 2 Sheets- Shet 2 INVENTbRs. a Z I).

412 'ITORNEYS.

veg v not/v wste WW W -i Patented June 19421 msirnon AND arr-mains roll raonucme nourm BAT'IS;

'Harvey B..Lindsay, Evanstonlan'i Norman Bl Easter, Park B168 Illq'assignors to Dry-zero Oorporation, Chicago, m, a corporation ofll-' 3 linok Application May 23,

This invention relates to improvements in methods and apparatus-for producing a bound batt of fibrous insulating material. The inven- 1 tion is. particularly designed for application to Ceibafiber, commonly known as Kapok, and similar natural fibers which are particularly useful for their heat insulating properties.

It has heretofore been, considered impossible to apply adhesive binding materials a body of such fibers so as to form-a coherent mass, as for instance in the shape of insulating blankets or strips, and yet to maintain the .desired light and highly resilient qualities of the fiber and without afiecting its insulating properties.

. Among the objects of our invention is to produce a light'and highly resilient fibrous batt in which the surfaces of the fibers or any appreciable part of such surfaces are not coatedor covered with'binding material, but in which the adjacent fibers are bound or attached to each other only at occasional, minute points of contact, leaving the fibers between such points free to flex independently in theirnatural state. In way the desirable characteristics of the fiber or of the fiber as awhole are not inany way interfered with by the binder, or by any substantial penetration of the fiber due to to absorption of the binder. V

' A further object of our invention is to produce a batt of thickness up to several inches, so lightly but firmly bound together that its weight may be reduced to less than one-half pound per cubic foot, and yet so resilient that it, may be compressed to one-eighth its thickness, and after release, regain its normal thickness, and so firm that it may be cut in an direction, and the fibers along the edge retain their proper position.

It has been common-practice to introduce an adhesive or binder into a body of lightly matted fiber material so as to bind it into a more or less pliable blanket, sheet or block. This is usually done either by spraying successive thin layers of the fiber and placing one layer upon another,

' l or else by saturating or submerging the fiber in a liquid vehicle containing the binder, doctoring the mixture to the desired thickness, and dryin: it. v

For such purposesas heat insulation, however,

it is important ,that neither shall the nature of the fib'er surface be changed, as by coating or by substantial deposit thereon, nor that the characteristics of the material composing the fiber be attested by penetration or absorption of the binder or vehicle. In the case of heat insulation, the microscopic smoothness and. instant less, No. 275,208 19!. lsa-z'n resilience I of the individual fiber throughout the entire body of insulating material form one of the controlling factors of insulatingvalua; Hence where the fiber used poss sesses these qualities to a high degree, as for instance in the case of the Ceiba fiber and other natural fibers of a similar character, it is important that their surfaces shall not be coatedor receive any substantialdeposit thereon of a binder, such as the ordinary-adhesives, which do not have the same surface qualities.

Furthermore, as is well known, the introduction of solid matter into the fibral construction of applicable or resilient fiber renders thelatter brittle or tends to destroy its resilience. It is extremely desirable that light fibrous insulating materials should retain their resilience -indefi-' niteLv so as not to break down, sag or settle in 4 an insulated wall structure under movement or 2 vibration.

- it is for these reasons that sofar as we are aware, no light fiexible insulation composed of fibers bound together has previously proved lasting, eflicient or satisfactory. particularly for-uses where movement, impact or vibration are to be encountered;

In carrying out our invention, we have dis- I covered that the binder or adhesive must be introduced to the fibers in such a form and man'- ner that it will not tend to spread out over a substantial part of the fiber surfaces, but on the contrary will tend to stick on the fiber surfaces as minute droplets ready to adhere to another fiber as soon as the other fiber touches that point,

thereb forming a bond as the fiber hardens at a single point only and without any "appreciable coating of the fiber;

To achieve this we have found it desirable to use such a combination of fiber, and binder solu- 40 tion or emulsion sprayed thereon, that sufiicient surface tension of the fiber is set up on the binder.

liquid to cause the mist droplets to remain in that form after alighting on the fibrous surface, and not to spread or "wet the fiber substantially 4 beyond the initial point of settlement. As before stated, the ceiba fiber previously referred to, has not only notable heat insulating properties, but

it is one of a number of natural fibers having a waxy constitutent which sets up a high surface 5 tension on water. We find that fibrous material having these characteristics can be successfully bound into batts by proper application of a water solution or emulsion of'an adhesive, containing no sort of soap or oil or other wetting agent,

in such-a manner as to produce what might be 2- 2,288,095 termed a spot" or droplet binding as above described.

The methods of achieving the foregoing purposes and the product thereby produced may best be understood by reference to the accompanying drawings, in which- Fig. 1 is aiplan; view showing the principal portions of an apparatusforproducinga bound batt in the form of a continuous strip.

Fig. 2 is a side view of the apparatus shown in" Fig. 1.-

Fig. 3 is an enlarged detail'view taken on line 3-3 01' Fig. 1. s

Fig. 4 is a detail view showing a portion of the batt in bound IQ m afterit has passed through the apparatus shown in the foregoing figures.

"and arrangement of the eonduit lfl, it will be understood that air is forced as usual through .saidconduit at a predetermined speed from a suitable blower or'the like (not shown), and

' loose'fiber is fed into this air current by a pre- Fig. 5 is a fragmentary microscopic detail showing individual fibers greatly enlarged and illustrating more or less figuratively the arrangement by which the "adjacent fibers are connected together at certain points by individual droplets of binding material.

Referring to details of the apparatus illustrated in Figs. 1, 2 and 3 of the drawings, an air conduit ID for carrying loose fibers leads to a pair of vertically spaced rollers II and I2 havingopen screen surfaces l3 forming a somewhat restricted throat l4 therebetween, and having a suitable conveyor '|5, herein consisting of an endless belt |6 trained on a roller l1, disposed beyond said throat.

The screen 3 on rollersl and 2 is preferably of 'fine wire mesh, as for instance in the order of six' to ten mesh, to provide a substantial orifice area per square inch for passage of air therethrough. Said screening is mounted on rotating shafts l8 and I9, respectively, by means of a plurality of spaced circular discs 20, to

which the screening is suitably secured. The

roller shafts I3 and I9 are journalled respectively at opposite ends in upper bearing brackets 2| and lower bearing brackets 22, which in the preferred formshown are mounted for vertical adjustment toward and away from each other so as to regulate the height of the throat I 4 between the adjacent roller surfaces.

In the' form shown herein, this vertical adjustmentfiatejach end of the rolls is provided by mean's of twofupright supports 23, 24 mounted on a base member 25, as clearly shown in Fig. 2. The' j-supp'ort 23 passes vertically through the beating-brackets 2|"and 22, and has right and left {threaded connection in said brackets as shown, so-that the two brackets may be moved towardfand away'from each other by rotating the "support 23, as for instance by engaging the squared upper end portion 26 thereof with a suitable tool. The companion support 24 is-fixed on the base 25 so that the upper and lower bearing brackets 2| and 22 are slidably adjustable thereon. In the form shown a set screw 21 on bracket 2| is adapted to engage support 2'! to hold the bearing brackets in any desired position of adjustment.

The screen rollers II and I2 may be driven by any suitable power means (not shown) connected to the shafts and I9 so as to rotate them in opposite directions, as indicated by the arrows mFm'a;

determined rate by means familiar to the art, details of which need not be described herein,'as they form no part of the present invention. In the form of conduit shown in the drawings, a series of transverse baflle plates or rifiies 35, 35 are also mounted in alternate spaced relation along the top wall 36 and bottom wall 31, whereby substantially all of the fibers are caused to assume a generally parallel relation with each other in a direction transverse to the normal direction of flow of the flbers'through the conduit, and thus produce a so-called graining" effect in the final batt. -This means for graining the fibers is broadly disclosed and claimed in Patent No. 1,679,251 issued July 31, 1928, toHarvey B. Lindsay. While the spot binding process forming the subject-matter of the present application seems to give somewhat-better finished product where the fiber is thus grained, yet the same process can likewise be used without such graining.

Mounted in the conduit l0 adjacent the last baille or riflie 35 and directed generally toward the throat I 4 between the screen rollers II and I2, are a plurality of spray guns 40, 40 of any well known form, adapted to throw a very fine mist spray of liquid binding material. These guns are preferably mounted so that the direction of their discharge may be angularly adjusted. In the form shown, said'guns are individually supported in a series of elongated recesses 4|, 4| formed in the top'wall 36 of the conduit l0, said recesses each having an opening 42 in its front wall 43 through which the nozzle of its spray gun 40 is directed. The de sired adjustment of nozzles may be provided by slightly dishing or curving its respective front wall 43 and clamping the nozzle thereto for limited universal rocking adjustment by means of a nut 44 on the reduced outer end portion of the nozzle, asclearly shown in Fig. 3.

The spray guns 40 are adjusted to throw a laterally fanwise mist spray, and are preferably positioned at such a distance from the throat l4 that the spray discharge will become spent and be dispersed with a billowing movement in the I area substantially at and between the converg- Carried between each pair of upper and lower means, such as gears 3| meshing with gears 32 'm ing surfaces of the screen rollers H and 2 immediately in front of the throat l4. The liquid binder and compressed air are fed to the guns as usual through conduits 48 and 4.1, so as to force the resulting spray through-the nozzles at such a pressure that at the beginning of the aforesaid billowing movement the spray mist will be traveling at substantially the same speed as the fiberladen air at the same point. l I Control of the proper billowing point as "above described may be afforded to some extent by adjustment of fineness of the nozzle spray on the process, we find that a 2% solution of methyl I ferred materials suitable for utilization there-"- pushed away from the binder mist rather than intuit. When, however, the discharge begins- ;to billow out just before reaching the throat between the screenrolls, this condition changes,

will depend upon varying factors in each ini stance, and it may even be necessary to make readjustments due to temporary changes of at mospheric conditions, small changes of fiber density, and other apparent slight causes. As a practical method'of determining the proper ad- Justment at which the billowing mist will be, caused to spray uniformly over all of the air' outlet area at rolls ii and i2, and yet to keep the binder from excessive concentration at the throat surfaces, we have found this to be when thenozzles are so directedwithout the air current in the conduit-that the mist spray strikes the screen surfaces about at the point where it begins to billow.

. It will be observed in Fig.3 that the top wall 38 of the conduit l0 approaches 'to within a fraction of an inch of the adjacent screen roll surface 13, and that the remainingv gap is closed by a soft and resilient lip 41 such as leather,

felt or hair brush strips 'stiff enough not to blow out, yet soft enough not to hurt the screening of the rolls. The bottom wall 31 is preferably provided with a hinged end portion 48 adjacent the bottom roller l2, adjustable by suitable means such as a bolt 49 on arm 49 operating 5 in a slotted bracket 50, as shown in Fig. 3, so as to enlarge or decrease the size of the throat at the billowing area of the mist when desired. The

hinged portion 48 is also provided with a resilient lip 52 similar to the lip 41 on the upper wall.

The side walls 54 of the conduit ID are preferably spaced from each other substantially the same distance as the total length. of the screen rollers II and i2, and are continued by tongue portions 55 extending at least to the vertical center line of the rolls. These tongues may be edged with suitable hair-brush strips where they contact the screening as indicated at 56.. As the correspondingly different dimensions.

As a binder suitable for employment in our cellulose in water, or a mixture of commercial hesive with an equal amount of water to forman. emulsion, makes a satisfactory binding agent ers having similar characteristics may also be used with our process.

With the apparatus above described and prewith now in mind, the operation of the process may be generally. described as follows:

As an air-borne fiber passes thefirst part of the nozzle discharge spray, it'tends to be and as both mist and rrrb rne fiber approach *F'lextite" which consists of a latex base ad- 2,288,095 p -3 fiber are led against the screen surfaces of the,

rolls and each other by the air escaping through said screen surfaces, some of the microscopicglobules of mist carried by the air are forced to alight on the fibers, while the balance of the mist passes out through the screen rolls. In detail, it appears that a fiber momentarily held against the screen and having several globules of binder mist deposited on it, is followed by another fiber which slides along the first until it hits one of the binder globules, whereupon the two fibers are stuck together at the point of such globule, and so on successively. As the rolls continue .to rotate, the fibers on the two rolls, building continuously to a depth of from a fraction of an inch to two or three inches thick (depending upon the controlled volume of fiber for the thickness of batt desired), meet each other and are in turn bound bothby free globules on the surface fibers of each lot, as well as by some small amount of mist that may seek'outlet through the porous batt itself. Fig. 5 illustrates in a more or less figurative way how the individual dot or globule points of adherence occur'between adjacent fibers, as indicated at 58,

v The screen rolls then compress the newly and continuously formed batt considerably to a degree depending on the lightness and resilience of the fiber being run, and it comes out and is deposited on the moving conveyor I5 as a uniform batt, as indicated at 59 in Fig. 4, the fibers 1 of which throughout areadhered to each other as previously described.

It is usually necessary to dry out the binder in the batt by-any suitable means before the bound batt is ready for use. In practice, however, we find that this drying process is relatively quick and easy work because the fiber is perfectly excepting at each microscopic binding dot, and the latter are so minute that p drying requires little more than getting dry air to pass through the batt.

It will be understood that various modifications may be made in the apparatus shown and described herein as illustrative "of a means of carrying out our invention and producing our improved'product. For instance, the shape of the conduit zcan be varied, and spray guns or rolls are adjustable-vertically for different thick- 5 'nemes of batt, these .tongues may be replaced, if necessary, with "similar tongue portions of nozzles can mounted at the sides, bottom or foratedcarriers for the fiber stream, assisting in shaping-the fibers into final batt form; but other forms of perforated carriers can be utilized for the same purpose.

It is apparent that these screen surfaces adjacentthe throat serve an important function in arranging the fibers in their final adhering positions, as it will oftenbe noted in practice that-the batt, as viewed from the side edge thereof, shows that the .fibers finally have a distinctly herringbone or V-shaped pattern, as clearly'indicated in Figs. 1, 3 and 4. We attribute this to the action of the screen roller surfaces on the fibers at the throat M, where final adhesion between adjacentfibers is effected.

Although we have shown and described certain embodiments of our invention, it will be understood thatwe do not wish to be limited tov the exact construction shown and described, but that various changes and modifications may be made without departing from the. spirit and i scope of our-invention 'as defined in the apthe same outlet area, they mingle. As successive. P n edclaims.

fibers having a relatively high wet-resistant surface, which comprises blowing loose fibers through an air conduit, spraying an emulsified liquid adhesive, into the conduit in the form of a fine mist so as to-deposit individual minute globules onlocalized surfaceareas of the fibers without substantial penetration thereof, and.

passing the body of fibers between opposed perforated carrier surfaces in the area of said mist spray. 1 ,7

2. Apparatus for forming a bound batt of for blowing loose fibers, two driven rollers having adjacent perforated surfaces spaced from each other so as to form a relatively restricted throat at the discharge end of said conduit, and nozzle means for spraying a liquid binding material into said fibers at a point adjacent said throat, said nozzle being disposed wholly within the line of air flow and arranged so.that the billowing action of the spray occurs in the area immediately adjacent tire rollers and said throat.

3. The method of forming a bound batt of fibers which comprises blowing the loose fibers through an air conduit, spraying an adhesive in liquid 'fbrm into said conduit in a fine mist formed of microscopic globules so as to deposit said globules individually on minutely localized surfibrous material, which includes an air conduit through anair conduit-"spraying an adhesive in liquid form into said conduit in a fine formed of microscopic globules so astodeposit said'globules individually on minutely localized surface areas of said fibers, without substantial' wetting of said fibers, and partially compressing the body of said fibers to form a batt.

6. The method of forminga bound batt of" fibers having a relatively highwet-resistant surface, which comprises blowing the loose fibers through an air conduit, spraying an adhesive liquid into said conduit in a fine mist formed 1 of said fibers between said points of adhesive connection, and partially compressing the body of fibers to form a batt.

, 7. The method of forming a bound batt of fibers having a relatively high wet-resistant surface, which comprises blowing the. loose fibers face areas of said fibers, without substantial I wetting of said fibers, and partially compressing the body of said fibers to form a batt.

4. The method of forming a bound batt of fibers which comprises blowing the loose fibers through an aii conduit, spraying an adhesive in liquid form into said conduit in a fine mist formed of minute globules, and causing said mist spray to move in the same direction and at substantially the same velocity as the fiber-laden air in said conduit so that said globules may settle individually on the surfaces of said fibers and thereby provide individual points of adhethrough anair conduit, spraying an adhesive liquid into said conduit in a fine mist formed of minute globules, with said mist spray moving in the same direction and at substantially the same velocity as the fiber-laden air in said conduit so that said globules may settle individually on the surfaces of said fibers and thereby provide individual points of adhesion between adjacent fibers at separated points of contact, and partially compressing the body of fibers to, form a batt.

8. The method of forming a bound batt of fibers'having a relatively high wet-resistant surface, which comprises blowing the loose fibers through a conduit, by air flow directing a spray of an emulsified liquid into the conduit in the same direction as the airflow to form a mist of microscopic globules and causing the spray to move at substantially the same velocity as said fibers so that said globules 'may settle individually onminutely localized surface areas of said fibers, and passing the body of fibers between opposed perforated carrier surfaces within the area of said mist spray to partially compress said fibers into'a batt.

. HARVEY B. LINDSAY.

. NORMAN R. EASTER. 

